The present invention relates to a multipole excess current switch of the type composed of a plurality of single pole excess current switches and a corresponding number of housings.
In such a multipole switch, only one of the single pole switches has the purpose of switching on and off a push button subjected to the action of a disconnection spring, the push button acting, via an operating rod rigidly connected therewith, on a shaft guided for transverse movement in the housing. An angle lever is rotatably mounted on the shaft and is subjected to the action of a release spring. The angle lever forms a bell crank together with a one-armed lever articulatedly connected to a contact bridge, the acticulation shaft of the one-armed lever being guided in grooves of the housing. A locking pawl is provided for arresting the shaft in the ON position of the contact bridge. A pivotally mounted release lever is provided for securing the angle lever against rotation when the switch is in the ON position, which release lever is pivotally urged into its ineffective position by a U-shaped bent bimetal strip.
The shaft extends into those single pole excess current switches which do not have push buttons, but each of which does have a bell crank composed of an angle lever rotatably mounted on the shaft and a one-armed lever, a contact bridge hinged to the one-armed lever, a released lever and a U-shaped bent bimetal strip acting thereon.
A multipole excess current switch of this kind is disclosed, for example, in U.S. Pat. No. 3,706,057, wherein the shafts of the release levers are coupled to one another, so that when an excess current occurs in one single pole excess current switch, all the release levers have to be pivoted by the one bimetal strip. In this universal-pole disconnection a relatively powerful force must therefore be exerted by the one bimetal strip.